It is sometimes necessary or desirable to discharge a gas to the atmosphere while shielding the gas conducting system from the dynamic pressure of the wind. For example, in making field measurements of gas flow, it may be necessary to discharge the gas to the atmosphere. In this instance, it is necessary to shield the flow meter from the dynamic pressure of the wind. If this is not done, the accuracy of the measurements may be greatly reduced.
Various attempts have been made to provide some degree of isolation of a system from the dynamic pressure affects of the wind. For example, Silverman U.S. Pat. No. 2,878,744, Moran U.S. Pat. No. 2,701,999, Mueth U.S. Pat. No. 2,090,392, Reed et al U.S. Pat. No. 3,231,004 and Miller U.S. Pat. No. 3,168,861 deal with systems to provide draft control or protection for heaters or vents, and Herick U.S. Pat. No. 2,284,147 provides an apparatus for preventing rain or foreign materials from entering the upper end of a pipe. Price U.S. Pat. Nos. 3,310,257 and 3,214,115 and DeLeo et al U.S. Pat. No. 3,318,146 provide apparatuses for pressure measurement for aircraft usage. Anderson U.S. Pat. No. 3,034,353 provides a static pressure probe which is said to provide the same static reading regardless of its orientation. None of the approaches discussed above provide the degree of shielding which is desired for some of the more pressure sensitive gas supply systems.